Heterotrophic Bacteria from an Aztec Archaeological Zone

The archaeological zones suffer alterations because they are exposed to diverse physicochemical and biological processes such as changes in temperature and humidity, the dissolution or crystallization of salts (carbonates, sulphates and silicates), the development of microbial colonies producing pigments, organic acids, siderophores, enzymes, etc. The incidence of these processes affects the stone monuments structurally and aesthetically. Ten strains isolated from the archaeological zone of Malinalco were tested for the production of siderophores with Luria Bertani Cromazurol S (LB-CAS) media and for the production of organic acids with Bromocresol Green Foster agar (presumptive test) and Foster agar with calcium carbonate (confirmatory test). The halos produced were measured at 24 and 48 hours. Subsequently, routine biochemical tests were performed to determine a presumptive genus and were determined taxonomically by analysis of 16S RNA sequences. The results show that the heterotrophic bacteria studied are related to the production of different metabolites such as organic acids and siderophores that contribute to the deterioration of archaeological monuments, among the genera found are Bacillus, Arthrobacter, Pantoea and Proteus.